1. Field of the Invention
This invention relates to a surgical instrument which utilizes irrigation, aspiration and ultrasonic frequencies to disintegrate and remove a cataract lens from an eye and, more particularly, to a tip adapted for use with an irrigating/ultrasonic handpiece for insertion removing the lens/cortex of the eye.
2. Prior Art
An opaque or cloudy cataract lens must be replaced to restore vision. A technique for extracting the lens cortex from an eye known as phacoemulsification and aspiration has been developed by C. D. Kelman and A. Banko and described in U.S. Pat. No. 3,589,363. In this technique, an ultrasonic vibrating tip is inserted through a small corneal incision wherein the tip contacts the lens and disintegrates and emulsifies it with an irrigating fluid. A delivery tube coaxial with the tip provides a flow of saline into which the disintegrated lens readily disperses to form an emulsion. The emulsified lens tissue is then aspirated through a second channel in the tip and the lens is thereby removed.
Phacoemulsifier devices comprise a power supply, and, in combination, a handpiece and a tip portion. Typical of such handpiece and tip combinations are U.S. Pat. No. 4,040,414 to Suroff, U.S. Pat. No. 4,988,334 to Hornlein, et al., and U.S. Pat. No. 4,886,491 to Parisi, et al. Perhaps representative of the art in phacoemulsifier handpieces and tips is U.S. Pat. No. 5,162,044 to Gahn, et al., the contents of which are incorporated herein by reference. Gahn describes a phacoemulsification probe which uses ultrasonic frequencies to treat cataracts. His probe includes a rotatable handle to facilitate repositioning of the needle in the eye during surgery while maintaining a comfortable and secure grip on the instrument.
Gahn describes the general problems relating to comfortable grips. According to Gahn, the rotatable handle provides the surgeon with the degree of freedom needed for comfortable lens removable. There are however certain problems associated with the straight tips depicted in Ghan which were not discussed. Among these is the fact that the axis of the tip is coaxial with the axis of the handpiece and, due to projection of the eyebrow, the lens of the eye must be entered at an angle requiring repositioning of the needle tip to access the entire lens. Due to the fact that the prior art phacoemulsifier handpieces utilize a straight needle they are not ergonomic and are difficult to use. This, is turn makes it more difficult for surgeons to learn the phacoemulsification technique. Further, the straight tip increases the likelihood of wound enlargement which can result in loss of anterior chamber pressure, iris chafing and corneal burns. It is desirable to provide both a phacoemulsifier handpiece having irrigating and aspirating capabilities and an ultrasonic handpiece having irrigation and aspiration capabilities (alternatively referred to herein as an "I/A ultrasonic handpiece") with a tip comprising a needle wherein the needle is bent or angled so as to afford comfortable access to the lens of the eye through an incision in the eye.